1. Field of the Invention
The present invention relates generally to a screw assembly and method for controlling tolerances related to stacking components, and more particularly to a screw assembly and method which can provide for interlocking of adjacent components, while maintaining locational tolerances such as a constant spacing between the components.
2. Description of Related Art
Various mechanical applications involve adjacent structural components, some of which may be in contact with one another, and others which may instead be spaced apart from one another. In some situations where adjacent structural components are spaced apart, tight locational tolerances may play a significant role in performance or effectiveness of the particular application. That is, maintaining a particular spacing between components in some systems or applications may be important to the functionality of the system.
In some of these applications, a particular spacing between adjacent components may be difficult to establish and maintain without slight variations, for example, minor increases or decreases in the gap or spacing size. In these cases, it may be difficult to establish a stable structural connection between components, or a desired gap or spacing may be either too large or too small to create a sturdy or effective connection using traditional methods.
One such application may be in the field of phased array antennas, which have seen an increase in the range of application in recent years in fields such as the defense market, including applications in communications and radar systems, as well as in various other commercial markets. For example, a phased array antenna developed by the Raytheon company, may include a radiator having a plurality of transmit/receive integrated microwave module (TRIMM) plates or columns arranged in a column assembly, and a plurality of radiating elements extending from each of the columns in the column assembly. Polarization of such a phased array antenna depends on, for example, the orientation or the alignment of the electric field radiated by the phased array antenna. A particular array orientation generates a fixed electric field alignment across all the elements of the assembly, and as such, small variations in spacing between the columns in the column assembly may have a large impact on the effectiveness, stability, and/or optimization of certain performance characteristics of the phased array antenna. Therefore, positional precision is more important for certain portions of such column assemblies, for example, the radiating elements.
In these phased array antennas, if adjacent plates or columns are stacked to contact one another, the relative positioning between radiating elements may be affected by manufacturing variations in the plates or columns, for example, variations or inconsistencies in plate thicknesses. Furthermore, in such column assemblies, as the number of columns in the column assemblies increases, any plate inconsistencies may cause additional deviations from a desired spacing between the radiating elements, as error may be compounded based on the increased number of columns, and performance degradation of the antenna as a whole may further be magnified. As such, it may be desirable to provide a certain amount of clearance between adjacent plates, in order to eliminate or reduce spacing inconsistencies between the radiating elements that may be caused by manufacturing variations of the columns. In such arrangements, the columns can therefore be aligned according to positioning of the radiating elements, and the plates may then be secured in the desired positions to eliminate or reduce such variations.